Study Designs in Genetic Epidemiology

Genetic epidemiology, as a relatively new issue, aims to explore the independent role of genetic-environmental determinants of diseases. Genetic epidemiology studies, depending on the objective, encompass the most preliminary surveys from the attempts to find family history in the occurrence of diseases to the most advanced surveys including specific strategies by clinical trials in the prevention of genetic diseases. Different objectives in genetic epidemiology studies require special methods and study designs. In this review, chief designs including familial aggregation, heritability, segregation, linkage, and association are evaluated; likewise, the purpose of diverse kinds of studies and analyses is briefly discussed. The utilization of study designs and related analyses according to the aims are the main issues and necessary in the accurate implementation of the study. Some methodological issues in relation to studies on tuberculosis are also reported. Attention to these issues might be useful in the implementation of these methods in the studies designed for the prevention and treatment of genetic disorders.